Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale
Changes in rates of respiration and net photosynthesis in Stereocaulon paschale (L.) Hoffm. in relation to temperature, moisture, and light have been documented for a woodland population collected in the Abitau–Dunvegan Lake area of the Northwest Territories. The temperature optimum for net photosyn...
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Canadian Science Publishing
1978
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Online Access: | http://dx.doi.org/10.1139/b78-338 http://www.nrcresearchpress.com/doi/pdf/10.1139/b78-338 |
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crcansciencepubl:10.1139/b78-338 2023-12-17T10:26:43+01:00 Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale Kershaw, K. A. Smith, M. M. 1978 http://dx.doi.org/10.1139/b78-338 http://www.nrcresearchpress.com/doi/pdf/10.1139/b78-338 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Botany volume 56, issue 22, page 2825-2830 ISSN 0008-4026 Plant Science journal-article 1978 crcansciencepubl https://doi.org/10.1139/b78-338 2023-11-19T13:38:45Z Changes in rates of respiration and net photosynthesis in Stereocaulon paschale (L.) Hoffm. in relation to temperature, moisture, and light have been documented for a woodland population collected in the Abitau–Dunvegan Lake area of the Northwest Territories. The temperature optimum for net photosynthesis is about 20–30 °C and not 0 °C as has been previously reported in the literature. Maximal rates of net photosynthesis are only developed at low levels (100–150% water content by weight) of thallus saturation, suggesting a good degree of adaptation to the xeric conditions normally found in spruce–lichen woodland. Similarly the relatively high light requirement of 1000 μE ∙ m −2 ∙ s −1 correlates well with the open nature of lichen woodland and especially with the disappearance of Stereocaulon paschale in old woodland with the closure of the canopy.The sensitivity of Stereocaulon paschale, when dry, to thermal stress is examined in detail and even the moderate thallus temperature of 35 °C is shown to be highly stressful to this species. Surface temperatures in the low arctic are often above 35 °C and over recently burnt surfaces, temperatures above 45 °C occur on a regular basis. Thus the delayed entry of Stereocaulon paschale into the successional sequence reflects its extreme sensitivity to thermal stress. With the gradual accumulation of an organic layer and an enhanced retention of soil moisture over the initial 60 years of succession there is a significant reduction in both the sensible heat flux and the surface temperatures. At the same time, tree growth leads to a sharp decrease in direct radiation, and the combination of these two developments results in a much cooler surface and one which can be colonized by Stereocaulon.It is suggested that thermal stress tolerance of lichens in an air-dry state, to either high or low temperatures may be centrally important to their overall ecology. Furthermore the net photosynthetic response pattern to temperature, moisture, light, and time of year may, in fact, play a ... Article in Journal/Newspaper Arctic Northwest Territories Canadian Science Publishing (via Crossref) Arctic Northwest Territories Dunvegan ENVELOPE(-118.603,-118.603,55.917,55.917) Dunvegan Lake ENVELOPE(-107.167,-107.167,60.134,60.134) Canadian Journal of Botany 56 22 2825 2830 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Plant Science |
spellingShingle |
Plant Science Kershaw, K. A. Smith, M. M. Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
topic_facet |
Plant Science |
description |
Changes in rates of respiration and net photosynthesis in Stereocaulon paschale (L.) Hoffm. in relation to temperature, moisture, and light have been documented for a woodland population collected in the Abitau–Dunvegan Lake area of the Northwest Territories. The temperature optimum for net photosynthesis is about 20–30 °C and not 0 °C as has been previously reported in the literature. Maximal rates of net photosynthesis are only developed at low levels (100–150% water content by weight) of thallus saturation, suggesting a good degree of adaptation to the xeric conditions normally found in spruce–lichen woodland. Similarly the relatively high light requirement of 1000 μE ∙ m −2 ∙ s −1 correlates well with the open nature of lichen woodland and especially with the disappearance of Stereocaulon paschale in old woodland with the closure of the canopy.The sensitivity of Stereocaulon paschale, when dry, to thermal stress is examined in detail and even the moderate thallus temperature of 35 °C is shown to be highly stressful to this species. Surface temperatures in the low arctic are often above 35 °C and over recently burnt surfaces, temperatures above 45 °C occur on a regular basis. Thus the delayed entry of Stereocaulon paschale into the successional sequence reflects its extreme sensitivity to thermal stress. With the gradual accumulation of an organic layer and an enhanced retention of soil moisture over the initial 60 years of succession there is a significant reduction in both the sensible heat flux and the surface temperatures. At the same time, tree growth leads to a sharp decrease in direct radiation, and the combination of these two developments results in a much cooler surface and one which can be colonized by Stereocaulon.It is suggested that thermal stress tolerance of lichens in an air-dry state, to either high or low temperatures may be centrally important to their overall ecology. Furthermore the net photosynthetic response pattern to temperature, moisture, light, and time of year may, in fact, play a ... |
format |
Article in Journal/Newspaper |
author |
Kershaw, K. A. Smith, M. M. |
author_facet |
Kershaw, K. A. Smith, M. M. |
author_sort |
Kershaw, K. A. |
title |
Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
title_short |
Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
title_full |
Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
title_fullStr |
Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
title_full_unstemmed |
Studies on lichen-dominated systems. XXI. The control of seasonal rates of net photosynthesis by moisture, light, and temperature in Stereocaulon paschale |
title_sort |
studies on lichen-dominated systems. xxi. the control of seasonal rates of net photosynthesis by moisture, light, and temperature in stereocaulon paschale |
publisher |
Canadian Science Publishing |
publishDate |
1978 |
url |
http://dx.doi.org/10.1139/b78-338 http://www.nrcresearchpress.com/doi/pdf/10.1139/b78-338 |
long_lat |
ENVELOPE(-118.603,-118.603,55.917,55.917) ENVELOPE(-107.167,-107.167,60.134,60.134) |
geographic |
Arctic Northwest Territories Dunvegan Dunvegan Lake |
geographic_facet |
Arctic Northwest Territories Dunvegan Dunvegan Lake |
genre |
Arctic Northwest Territories |
genre_facet |
Arctic Northwest Territories |
op_source |
Canadian Journal of Botany volume 56, issue 22, page 2825-2830 ISSN 0008-4026 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/b78-338 |
container_title |
Canadian Journal of Botany |
container_volume |
56 |
container_issue |
22 |
container_start_page |
2825 |
op_container_end_page |
2830 |
_version_ |
1785578455591550976 |